How do I get wi fi internet in my shed?

I have a BT internet router which gives me WiFi in the house. I have a large shed/garden building which is about 150 meters from the house and in which I have a craft room/games space. It has a wired ethernet connection from the house but I would like to have wi fi down there. Is there any problem with just connecting a wireless access point? Which one would people advise? By the way, I know absolutely nothing technical about these things....

Because the outbuilding is relatively small, something like this is likely to be ideal. By default it should be plug 'n' play so just plug it into an electrical socket, connect the Ethernet cable, and you'll find the wireless-network name and password on the device's sticker.